Hello @Salka, Milan,
Thank you for posting in our Q&A forum.
The user accounts or groups with red question mark may have been existed on your machine in the past. However, they did not exist now.
These permissions should be useless, and if you really don't need them, you can delete the permission entries with the red question mark.
For more information, here is a similar thread for your reference.
https://answers.microsoft.com/en-us/windows/forum/all/who-is-the-unknown-user-with-a-red-question-mark/5e5ecb2e-67aa-417a-b04c-ec27d2f738b3
If you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou
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